Kill the Bill

Autonomous FinOps AI that cross-checks spend and usage data to eliminate wasted SaaS costs, negotiate renewals, and optimize company software budgets.

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Inspiration

Every company wastes thousands on unused software subscriptions, tools that continue billing even when no one logs in. Inspired by apps like Rocket Money for individuals and the complexity of enterprise SaaS management, we wanted to build an AI-powered solution that could automate cost optimization across departments. That idea became Kill the Bill, an intelligent assistant that hunts down waste before finance ever notices it.

What it does

Kill the Bill connects to company transaction data through the Knot TransactionLink API to identify:

Duplicate or overlapping SaaS tools

Subscriptions with no recent activity or login

Vendors charging above market rates

Department-specific waste where one team uses a tool while others don’t

It then computes a WasteScore using an ML model and automatically drafts cancellation or negotiation emails, helping companies save up to 30% of their SaaS costs.

How we built it

We built a FastAPI backend that fetches and normalizes data from Knot and runs it through a scikit-learn logistic regression model to compute WasteScores. A React + Tailwind dashboard displays live spend, top vendors, and potential savings per department. The system supports SKU-level detail, auto tax calculations, and an AI-powered email generator using OpenAI’s API. All data is stored in SQLite/Postgres, and the whole stack runs seamlessly through uvicorn and Vite.

Challenges we ran into

Mapping fragmented transaction and SKU data from multiple merchants.

Handling multi-department subscriptions, where one team needs a tool another doesn’t.

Ensuring secure and stable integration with Knot’s development environment.

Time constraints in training and tuning a meaningful WasteScore model.

Accomplishments that we're proud of

Built a fully functional FinOps AI assistant in under 48 hours.

Successfully integrated Knot’s TransactionLink API for real merchant data.

Designed a clean, intuitive dashboard that visualizes spend and potential savings.

Created a scalable foundation that could serve startups, SMBs, and enterprises alike.

What we learned

How financial APIs like Knot structure real-world transaction data.

The complexity of cross-team SaaS ownership in large organizations.

How small data-driven insights can have huge financial impact.

The importance of balancing automation with human validation in financial tools.

What's next for Kill the Bill

Expand to production Knot API with full OAuth linking.

Add real-time cost anomaly detection and alerts.

Integrate taxation and policy compliance per jurisdiction.

Train a deeper AI model that learns from past cancellation outcomes.

Turn Kill the Bill into a true AI CFO Copilot, automating not just cancellations, but strategic software budgeting.

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